Back end of the line (BEOL) and middle of the line (MOL) metallization is becoming more challenging in advanced technology nodes due to the critical dimension (CD) scaling and process capabilities. For example, as technology advances in designing integrated circuit (IC) chips, the IC chips are required to become smaller and smaller which, in turn, raises problems of contact shorting with gate structures as one example. More specifically, in such scaled structures, shorts are likely to occur between the contacts of the drain/source regions and the metallization of the gate structure, itself.
By way of example, shorting between the contacts of the drain/source regions and the metallization of the gate structure can occur due to overlay or misalignment issues in the masking step of the patterning processes. As another example, the etching processes for forming the interconnect (contact) to the drain and/or source contacts can corrode the sidewalls of the gate structures, exposing the metallization of the gate structure, itself. In subsequent metallization processes, the metal material for forming the contact structure can then electrically contact the metallization of the gate structure, resulting in a short.
Other issues with scaling of the devices include, e.g., metallization to the source and drain contacts or other metallization, requires tip-to-tip configurations at a contact space equivalent to one contacted poly pitch (cpp). This requires metal extensions past the contact to maintain yield; however, such extensions hurt scaling and add extra parasitic capacitance due to an extra wire run. In addition, as a potential alternative, super via structure integration is very difficult, requiring extra fabrication processes, potentially also hurting scaling. As to the latter point, the super via structure requires a large cross-section of the via (opening) to ensure that metal material can adequately fill the super via structure without the formation of airgaps, which can significantly affect parasitic capacitance and resistance due to the extra needed metal material.